<strong>AYUDA, HE INTENTADO DE TODO PERO NIO SÉ QUE ESTÁ MAL 😦</strong> <code>Traceback (most recent call last): File &quot;C:\Users\Le...

Hola, yo tenia el mismo error. Podrias revisar si en templates/index.html este el mismo texto de "No polls are available." ya que como el assertContains busca que contenga ese texto pues no lo encuentra y por eso te sale el error. Bueno ese podrias ser el error talvez, te dejo parte de mi codigo para que lo compares 😅 Espero te sea de ayuda

templates/index.html

{% if latest_question_list %}
    <ul>
        {% for question in latest_question_list %}
            <li><a href="{%url 'polls:detail' question.id %}">{{ question.question_text }}</a></li>
        {% endfor %}
    </ul>
{% else %}
    <p>No polls are available.</p>
{% endif %}

archivo test.py🐍

class QuestionIndexViewTests(TestCase):

    def test_no_questions(self): 
        """If no question exist, an appropiate message is displayed."""
        response = self.client.get(reverse('polls:index'))
        self.assertEqual(response.status_code, 200)
        self.assertContains(response, "No polls are available.")
        self.assertQuerysetEqual(response.context['latest_question_list'], [])

    def test_past_question(self):
        """Questions with a pub_date in the past are displayed on the index page."""
        question = create_question(question_text="Past question.", days=-30)
        response = self.client.get(reverse('polls:index'))
        self.assertQuerysetEqual(
            response.context['latest_question_list'],
            [question],
        )

    def test_future_question(self):
        """
        Questions with a pub_date in the future aren't displayed on the
        index page.
        """
        create_question(question_text="Future question.", days=30)
        response = self.client.get(reverse('polls:index'))
        self.assertContains(response, "No polls are available.")
        self.assertQuerysetEqual(response.context['latest_question_list'], [])